How are file permissions related to symbolic link permissions?

Question

linux

Created a symbolic link ln -s with full path as root.
There are two more users on the server.
How to make it so that someone who has only a link, and not the files themselves, could not change these same files?
How are file permissions related to symbolic link permissions?

Answer 1

How to make it so that someone who has only a link, and not the files themselves, could not change these same files?

This is always the case: i.e. access to a file is only determined by the owner/permissions of that file. The owner/permissions of the link don't matter.
No way. On Linux, link permissions are not used in any way and cannot be changed, see for example man 7 symlink .

Answer 2

The link does not have its own rights, the file's rights are used. Set the correct permissions on the file itself.

Answer 3

groupadd rw
usermod -a -G rw user1
chown root:rw filename
chmod 775 filename
newgrp

And do not change the rights to a symbolic link in any way, it is always 777 on it. This is because there is no such thing as "read the link" or "write the link".